The 4 Seasons

This month's PCAGOE challenge is entitled The 4 Seasons. We were to interpret that in any way we wished as long as the all 4 seasons were represented. I've always admired the paintings of trees with the changing seasons so I chose that as my starting point.
I have chosen a focus for 2016. I plan to make a wall piece a week for the 52 weeks to come. They will be of various sizes and backgrounds but will have more polymer clay than other medias in them. If any of you remember my year of bowls, where I made at least one bowl a week, you may remember that I thoroughly enjoyed that endeavor learning so much about the clay. I hope to enjoy this "form" focus just as much.
Using a flat canvas, bought at Michaels, I started by putting a wash of blue mixed with white glue for the background. I marked the area that would have the different seasons. I drew the tree onto the clay using a mg cane I had that looked like tree bark (of sorts). The tree is the same in all the seasons and I made little simple scenes of each season for each section. The clay was adhered with my tls formula. I then cut out the center to add a globe. After all, all the seasons follow earth's calling. Surely, my representation of seasons portrays my neck of the woods. It would an amazing study to do different parts of the world. That is a project for another day for sure.
I've already learned one lesson although I'm not sure that my conclusions are right. The globe "lifted" in the center. It cracked a little. The funny thing is that the canvas remained attached to the clay so the canvas is rounded where the globe is. I'm not sure if you can notice it in the photo.
I could always say that I meant to do that but I would rather take the chance that someone would know how it happened. It would be more fun to know so I could reproduce it at will. I welcome any and all theories on the matter.